Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Poster Presentations
*Department of Environmental Health, Harvard School of Public Health, Boston, MA, United States; †University of Milan and IRCCS OPMRE Foundation, Milan, Italy; and ‡Normative Aging Study, Veterans Administration Outpatient Clinic, Boston, MA, United States.
Abstracts published in Epidemiology have been reviewed by the organizations of Epidemiology. Affliate Societies at whose meetings the abstracts have been accepted for presentation. These abstracts have not undergone review by the Editorial Board of Epidemiology.
Background and Objective:
Leukocyte telomere length varies between individuals and decreases with age. Telomere length is inversely associated with cardiovascular disease (CVD) risk and is decreased by several risk factors for CVD, such as hypertension and obesity. No epidemiological study has been reported on the association between telomere length and ambient air pollution. We used longitudinal data from the Normative Aging Study (NAS) to investigate whether ambient black carbon concentration near homes is associated with decreased telomere length.
We measured telomere length repeatedly, approximately every 4 years from 1999 to 2007 using quantitative PCR. Here we analyze this outcome among 177 never-smoking men from the NAS cohort. Black carbon (BC) concentrations at each subject's home during the year prior to telomere measures were predicted based on a previously validated spatio-temporal model. Natural log- transformed telomere length was the dependent variable in linear mixed effects models with random subjects intercepts, adjusting for several potential confounders.
The mean (IQR) annual black carbon concentration was 301 (168 to 449) ng/m3. Over the 1 to 3 (median = 2) repeated measures per subject, telomere length, expressed as the ratio of telomere repeat copy number to single-copy gene copy number (T/S ratio), had geometric mean (geometric standard deviation) of 1.25 (1.32). Relatively wide temporal variability in telomere length was suggested by the intraclass correlation among repeated measures within subjects (r = 0.11), much smaller than expected due to random measurement error alone. We found that an interquartile range increase in BC was associated with a 5.7% decrease (95% CI −10.9, −0.2) in telomere length.
Shortening of telomeres may play an important role in the health effects of ambient particles, particularly those rich in black carbon, which are primarily related to automobile traffic.